1. Field of the Invention
The present invention relates to an improvement in a hammer of the type capable of use in a heavy-duty mill for tearing or shredding ductile metal in the form of scrap automobile bodies, sheet material and the like at the end of its useful life.
2. Background of the Invention
Hammer mills which are capable of breaking and/or disintegrating materials have been in use for a number of years, as have hammer mills which are capable of shredding or tearing solid materials. The scrap produced from a shredding or tearing process had been considered in many circles as being superior to that produced from other processes, such as compressing and shearing, and the industry has endeavored to provide structures whereby the preferred scrap may be obtained. Typical of such structures is that described in U.S. Pat. No. 3,727,848 to T. M. Francis. The Francis structure includes a rotary hammer assembly including a plurality of solid metal hammers having a body formed by a mounting end and a working end connected by generally outwardly inclined walls. The hammer is generally bell-shaped. Typically, a hammer of the type of the above patent is of a weight of about 250 pounds and supplies disintegrating power upon rotation around a "hammer circle" to tear ductile material which is fed into the hammer mill. While the hammer generally has performed satisfactorily, it has been found in certain instances such as when the hammer receives blows which are not straight toward the working face, that the body will fracture within the mounting end. This occurance requires that the hammer be replaced with consequent cost of a replacement hammer and downtime of the hammer mill. A further disadvantage of the hammer of the prior art is the weight itself. As may be apparent, the hammer, normally a cast article formed of steel or the equivalent, firstly, is quite expensive and, secondly, has a short working life as may be expected from the operation to which it is subjected. Consequently, any reduction in weight of the hammer will provide a savings in cost of hammers and the overall expense of the hammer mill operation.